So my daughter has the following car https://www.kidzauto.com.au/product/whi ... rd-ranger/ which i would like to convert to 24v, unfortunately i cant find a wiring diagram for it and the car has accessories such as a radio and lights so is not just a straight forward throw in another battery situation.

Is anyone able to shed some light on how to go about this modification.

Looks like it comes with a remote, which means it has a control board. Most likely electronic and unlikely to take 24V nicely. You would need some substantial rework to do the modification you want, and then there's the question of longevity for the motors themselves. What are your goals -- do you just want more speed? Do you want to keep the remote capability?